o_o
I took a semester of Japanese in college, so I kinnnnnd of know it lol. (I got a B TT^TT, but that was because I was lazy! I had the best sensei who was generous with my grade)
TAKE MY ADVICE WITH A GRAIN OF SALT
Ga deals with questions. You put ga at the end of the sentence. It works like a question mark.
I never mastered the wo, but it has to deal with an indirect object or something? Or a place?
Wa is practically used in everything /o/ safe bet is wa
do the wa wa wa wa
Our sensei had us learn hiragana first. He believes one day kanji will become obsolete because of how difficult it is to learn kanji. So that alone should tell you to learn hiragana and master it first. He had us learn hiragana, then we could learn katakana if we want(we had to master if we wanted to go to J2), then he gave us some kanji to remember. It was basic kanji like money, forest, water, etc. You should start slow. Learn how to make basic sentences. Don't focus on kanji first thing!! Also, hiragana is way more important that katakana. Katakana is used for foreign words!!
Definitely takes Aestivate's advice about writing it over and over again! That's how I mastered hiragana! (although I'm getting a little forgetful now since I haven't used it >>) I literally had a notebook full of hiragana+katakana from rewriting it over and over again. I'd stay many hours at night in the library constantly rewriting hiragana.
I also played a japanese mmorpg before which helped somewhat know what hiragana is what. I played the game PSO2, although it has an english patch, there's lots of hiragana and katakana around.